Copolymers of halogen containing ethylenically unsaturated monomers, such as the vinyl halides, are often prepared as aqueous latices or emulsions in which form they may be conveniently used as coatings, adhesives, paint bases and in various other types of applications. In many instances, particularly where they are being considered for use in building interiors or in use requiring their prolonged exposure to high temperatures, it is highly desirable and advantageous that these vinyl halide copolymer latices should display enhanced fire or flame retardant properties so that they may be safely employed in place of more costly materials.
Prior attempts to provide fire retardant, film forming vinyl halide polymer latices have involved the preparation of various polymeric compositions including copolymer latices of vinyl halides and the alkyl acrylate esters, copolymer latices of vinyl halides and vinylidene chloride and polyvinyl halide latices containing an extraneously added phosphate ester plasticizer. However, none of the latter approaches has proven to be completely satisfactory as the resulting products are found, in many cases, to be lacking sufficient fire retardancy, exceedingly soft, lacking in mechanical stability, readily degradable by ultra-violet radiation or subject to the gradual loss of their extraneously added phosphate plasticizers.
Thus, it is the prime object of this invention to provide novel, fire retardant vinyl halide copolymer latices which may be used in a variety of coating, binding, and laminating applications and which are characterized by their essentially complete freedom from the various disadvantageous properties heretofore associated with this type of product. It is a further object of this invention to provide a novel class of copolymers in the form of aqueous emulsions or latices which are particularly useful, as additives, for preparing fire retardant, polymer compositions which are in the form of aqueous solutions, suspensions or, most preferably, emulsions. Various other objects and advantages of this invention will be apparent from the disclosure thereof which follows hereinafter.